Switch and circuit for telephone-exchanges



(No Model.) 2 Sheets-Sheet 1.

J. J. OGONNELL. Y 7 SWITCH LAND GIEGUIT EOE TELEPHONE EXCHANGES.

No. 515,531. Patented Feb. 27, 1894,

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(No Model.) 2 Sheets-Sheet 2-.

' J. J. OGONNELL. SWITCH AND GIBGUIT FORTBLEPHONE EX'GHANGES.

No. 515,551. Patented P55. 27, 1894.

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' NTED STATES ATsN'r Fries.

JOSEPH J. OOONNELLpOF CHICAGO, ILLINOIS, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO THE AMERICAN BELL MASSACHUSETTS.

TELEPHONE COMPANY, OF BOSTON,

SPECIFICATION forming part of Letters Patent No. 515,531 dated February 27, 1894.

Applicationfilctl April 1'7, 1898.

To all whom it may concern.-

Be it known that I, JOSEPH J. OCONNELL, a citizen of the United States, residing at Chicago, county of Cook, State of Illinois, have 5 invented certain new and useful Improvements in Mechanism for Operating Circuit- Ohan gers in Telephone Systems, of which I do declare the following to be a full, clear, and exact description, reference being had to the w accompanying-drawings, forming part of this specification.

In the operation of telephone exchange systems it is customary to connect'the subscrib ers lines or trunk lines with the individual I5 spring-jacks of a switch-board by means of plugs attached to plug cords forming the terminals of such lines. When a connection is to be made, the operator, in manner well understood in the art, takes the plug cord of the subscribers line or of the trunk line that is to be plugged into the switch-board and having shifted a listening key in order to throw her own telephone into the desired circuit touches the plug to the metallic casing of the spring-jack of such circuit to test whether such circuit is busy or not. If the circuit is not busy, the plug is inserted in the springjack and the operator then reversely shifts her listening key in order to throw her telephone out of circuit.

One object of mypresentinvention is to provide means whereby as the operator lifts the plug to test the subscribers circuit and to insert the plug, the listening-key will be shift ed by the movement of the plug cord so as to throw the operators telephone into the desired circuit. It will be readily seen also that inasmuch as the means, whereby I attain this object of my invention, is susceptible of use 40 in any situation in which it may be desired to utilize the movement of the plug cord for controlling a circuit changer, my invention may be said to consist primarily in the combination with the plug cord and with the contact terminals of an electric circuit of a circuit changer adapted to be shifted by the plug cord as the latter is moved.

It is customary in the operation of telephone exchange systems to connect the exchange offices bytrunk lines, these lines usu- Serial No. 470,599- L'No model.)

ally terminating at one oifice in a trunk line switch-board and at the other office in individual plugs adapted to be inserted in the subscribers switch-board of such office. At the receiving office there are usually provided a number of signals (preferably incandescent lamps) arranged in local circuits, and corresponding in number and arrangement with the trunk lines; the purpose of these signals being to indicate to the receiving operator that a trunk line is to be dis-connected to be in readiness for subsequent service. These signals are placed in normally open circuits, which through the movement of suitable relays will be closed by the operator at the calling office and when so closed the incandescent lamps or other signals will come into play to exhibit to the operator at the receiving office that the corresponding trunk line is to be dis-connected. The operator at the receiving office will then dis-connect the trunk line plug from the subscribers jack and will open the local signal circuit in order to restore the lamp or other signal to its normal condition.

A further object of my invention is to provide means whereby the operator at the receiving office can by the simple act of restoring the trunk line plug to its seat or support thereby break the local signal circuit and throw the lamp or other signal out of action.

Figure l is a diagrammatic view of the tele phone system embracing two exchanges, my invention being shown as applied to the apparatus at one of the exchanges only. Fig. 2 is a view in vertical section through a plug cord guide and connected parts. Fig. 3 is a view in front elevation.

The exchange office A, which for convenience may be termed the calling office, is equipped with the usual apparatus such as the operators telephone and transmitter a and I), test and relay battery 0, order wire key d, multiple switch-board jacks f, shunt key g, &c., in usual circuits. A single subscribers line 2 (a metallic circuit) is shown as leading from the subscribers telephone 3 to the multiple switch-board of the exchange office A and this office is shown as connected with the exchange office B which may be we termed the receiving office by means of the order line G and a trunk line 11 each of these lines being shown as comprising two wires to form a metallic circuit. Trunk lines H in required number will connect the offices A and B, each of the trunk lines terminating in a spring jack Jat one office and in a switchcord plug M at the other office. One of the wires 5 of the trunk line H is broken at the oflice B the broken ends of this wire connecting to the contact springs 8 and 9 supported by the insulating block 10. To the block 10 are also attached the contact plates 11 and 12 to which connect the terminal wires 13 and 14 of the operators telephone circuit L. The wires 5 and 6 of the trunk line lead through the plug cord M to the switch plug M whereby connections will be made with the springjacks of a switch-board in manner well understood in the art.

A listening key (or other type of circuit changer), N is pivotally mounted as at 72 adjacent the ends of the contact springs S and 9, this key N having a shoulder n of insulating material which when thrust between the springs 8 and 9 will break their direct connection at 5 and at the same time will establish a connection between the springs and the terminal plates 11' and 12 which connect with the operators circuit, thus placing the operators telephone in the trunk line circuit. Each of the trunk line plug cords M extends upward through a suitable channel 15 and at a point opposite the key N the walls of the channel 15 are cut away as at 16 and 17 to permit the end n of the key N to engage with cord M. Suitable stops 18 and 19 (preferably spring plates) will limit the extent of movement of the key N which will rest normally against the stop 18 with its free end bearing against the plug cord M and in readiness to be lifted thereby. Hence it will be seen that when the operator at the receiving office B has been notified from the calling office A to connect trunk line H with the subscriber called for, the operator at office B will lift the plug cord M and plug M of trunk line H in order to make test and connection with the required circuit. As the plug cord is thus raised, the free end of the key N will be lifted thereby causing its insulated end n to force apart the contact springs 8 and 9 so establishing contact between these springs and the terminal plates 11 and 12 in order to throw the operators telephone into the trunk line circuit. Consequently, when the plug M is touched to the metallic casing of the proper spring-jack to make the busy test and the connection the operator is enabled without any separate act of shifting her listening key to determine whether the subscribers line is free or busy. In lifting the plug M to make connection there should be sufiicient slack in the cord M above the key N to permit the key to swing downward to its normal position after the plug has been inserted in the proper springjack as by this downward movement of the key the contact between the springs 8 and 9 will be re-established and the operators telephone will be thrown out of the trunk line and subscribers circuit.

The trunk line H is shown as connected in usual manner to a relay R which serves at proper time to open the local circuit S wherein is interposed the incandescent lamp or other signal by which the receiving operator is to be notified that the trunk line is to be dis-connected.

When the operator at the calling office A connects the subscriber with the trunk line H by inserting the plug V into the spring-jack of the trunk line the current from battery 0 will pass to the relay R thus energizing it and causing it to break the local signal circuit at T The signal circuit will thus remain broken and the lamp out of action until the subscriber is to be dis-connected, when the operator at the calling office will withdraw the plug V from the trunk line jack thereby throwing the battery 0 outof the trunk line circuit. The relay B being no longer energized, the spring 1" will shift the armature 'r of the relay causing it to complete the local signal circuit and consequently causing the signal lamp to show to the receiving operator that the dis-connection is to be made. The receiving operator will thereupon withdraw the plug M from the subscribers springjack and will break the local signal circuit in order to throw the lamp out of action. Heretofore this breaking of the local signal circuit by the receiving operator has been efiected by a key operated by hand, but by my present invention the act of returning the plug to its seat insures the breaking of the local signal circuit. The terminal wires and 31 of the local signal circuit S lead to a point adjacent the seat of the plug M, the wire 30 connecting with a contact spring 32 as shown, which is in contact at 33 with the terminal of the wire 31 when the plug M is connected with the spring-jack of the switchboard. An insulated spring plate or circuit changer 41 has its upper portion preferably curved and extending into the seat 40 of the plug M so that as the plug 1 is returned to its seat (under the stress of the weight W) the circuit plunger 4]. will force outward the block 34 and the upper end of the spring plate 41 causing it to force the spring plate 32 away from the terminal of the wire31 and consequently break at such point the local circuit and throw the signal lamp out of action.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. The combination with a plug cord and with the contact terminals of an electric air cuit of a circuit changer arranged to be shifted by said cord as the latter is moved, substantially as described.

2. The combination with a plug cord of a switch or key having a part extending into position to be shifted by said cord as the latter is moved, substantially as described.

3. The combination with a plug cord, of a switch or key having a pivoted arm extending into position to be engaged by said cord as the latter is moved, substantially as described.

4. The combination with a plug cord, of a guide for said cord having an open space at the side thereof and a switch or key having an arm extending through said opening and into engagement with the cord, substantially as described.

5. The combination with a trunk line having appropriate terminals and means for causing the passage of current over said trunk line, of a local signal circuit, a circuitohanger for controlling said local signal circuit argized to change said local signal circuit and whereby when the passage of current over said trunk line is broken at one of its terminals said relay will be (lo-energized and whereby when the circuit changer of the 10- cal signal circuit is operated, said local signal circuit will be again changed, substantially as described.

' JOSEPH J. OGONNELL. Witnesses:

JAMES H. PEIRGE, FRED GERLACH. 

